Deformable plate for variable condensers



Feb. 4, 1936. LUCAS 2,029,537

' DEFORMABLE PLATE FOR VARIABLE CONDENSERS Filed Aug. 24, 1951 ENTOR ATTORNEY Patented Feb. 4, 1936 PATENT OFFICE DEFOBMABLE PLATE FOR VARIABLE CONDENSERS Kurt Lucas, Berlin, Germany, assignor to Telefunken Gesellschai't fiir Drahtlose Telegraphic m. b. 11., Berlin, Germany, a corporation of Germany Application August 24, 1931, Serial No. 558.907

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This invention relates to variable condensers whose capacity curves are intended to be changed by transverse bending of one or more of the condenser plates making up the structure. More particularly the invention relates to a novel bendable plate construction.

In the uni-control of several variable condensers of a radio-receiving set it is important to so adjust the capacity characteristics of the different condensers that they will exactly correspond to one another in the desired manner throughout the whole range of regulation. Thus the problem may be to maintain a plurality of condensers at the same capacity throughout their range, or

again the problem may be to maintain a con: stant capacity difference between two condensers.

Applied to circuits the problem may be to main-' tain several circuits tuned to exactly the same frequency throughout a range of frequencies,'or o it may be to maintain a constant frequency differencebetween two or more circuits throughout a given range. It is also to be understood that the invention is also applicable when it is desired to give to two or more circuits varying predetermined frequency difierences throughout a given range. It is thus seen that the present invention includes the use of a variable condenser having a bendable plate in a tuned circuit which may take the form of a variable condenser and an inductance.

With these various problems in view it has been suggested in the prior art to furnish the various condensers with one or se" .ral auxiliary electrodes so thatthe'auxiliarfelectrodes are de- 5 formable at several points independently of one another. In this manner the distances between various local points of the, auinliary electrode in respect of the electrode capacitively cooperating therewith may suitably be adjusted independent- 40 y of one another in order to insure the desired trend or shape of capacity variation. The constituent parts of the deformable electrode are usually made of some elastic material, are separated from one another by slits or grooves, and

5 are adjustable by convenient regulating means such as a screw spindle.

However, an arrangement of the said nature seldom affords a chance for perfect balancing of the characteristics of the various condensers for all points of adjustment. The different segments of the adjustable electrode are bent in. dissimilar manners, and the slits separating them are of necessity associated with certain irregularities in adjustment.- But if the deformable electrode has no slits, then its deformation everywhere affects many October 16, 1930 also the deformation of the more or less closely adjacent points, so that if this reaction is to be avoided recourse must be had to a great number of adjusting means designed to fix as great a number of parts of the electrode in question as possible.

It is an'obiect of the present invention to overcome these diiiiculties by making the deformable electrodes of plastic metal gauze or braiding or the like.

Other objects of the invention will be apparent from reading the following detailed specification in connection with the drawing the single figure of which illustrates diagrammatically a condenser plate incorporating a possible embodiment of the invention.

In the drawing, I represents generally a plate of a variable condenser. The plate consists of a great number of thin radially positioned metal strips or spokes 2 emanating from a hub member adapted to be mounted on the usual tuning shaft, and visual wires 3 woven between said strips .polygonally or curvilinearly. It will be seen that with the construction shown the plate takes the form of a uniform piece of metal weaving structure which may be bent into any desired shape by means of the radially positioned metal strips 2. It is in this way that the plate I may be adjusted to be at varying distances from an adjacent plate in a condenser assembly so as to give the condenser the desired characteristics The wires B, which may be of any suitable shape and material, have been shown far apart solely for purposes of clearly illustrating the principles involved. However, it is to be distinctly understood that the wires 3 may be as closely woven as is desired and necessary to give the proper capacitive values.

While only one form of the invention has been shown, it is clear that many other embodiments will be immediately suggested to the skilled mechanic and that it is desired to limit the invention only by'the scope of theappended claims.

I claim:

1. Condensers especially of the multiple-unit .type, comprising one or more deformable electrodes for the adjustment of the capacity characteristic, with this characteristic feature that the deformable electrode surface is constituted by a'defonnable wire weaving or gauze.

2. Condenser according to claim 1, with this characteristic feature that the deformable electrodeis formed of thin strips radially positioned and interwoven with polygonal or curvilinear transversal wires or cross-strips.

3. In a variable condenser assembly provided with a hub member, a deformable plate compris ing a plurality of supporting members projecting from said hub member and a wire having a plurality of radial metallic, members, and flexible threads interwoven with said radial members to form a deformable surface. 1

6. A variable condenser plate comprising a plurality of substantially rigid members extending outwardly from a support, and metallic threads interwoven with said plurality of rigid members to form a deformable capacity surface.

'7. A variable condenser plate comprising a central supporting member, a plurality of rigid members extending outwardly therefrom and flexible wire threads interwoven with said rigid members to provide a deformable surface.

' KURT LUCAS. 

